javascript

console.log("ved varshney");

fullName="dhruv";

age=22;

price=99.99;

x=null;

y=undefined;

isfollow=true;

fullName=45;

console.log(fullName);

data types primitives

let age = 22;

console.log(age);

let name="ved";

console.log(name);

let price=100.78;

console.log(price);

let isfollow=true;

console.log(isfollow);

let u=undefined;

console.log(u);

let n=null;

console.log(n);

let x=BigInt("123");

console.log(x);

let y=Symbol("hello!");

console.log(y);

non primitive

const student={

fullName : "ved",

age:22,

cgpa:8.87,

ispass:true

};

console.log(student);

console.log(student["age"]);

console.log(student.age);

student.age+=1;

console.log(student.age);

console.log(typeof student.age);

operator and conditional statement

power operator

let a=5,b=2;

console.log(a**b); // 25

ternary operator

let age=16;

age>=18? console.log("valid"):console.log("not valid");

take input from user

let a=prompt("enter no.=")

console.log(a);

loops for-of

let str="ved varshney";

for(let a of str){

    console.log(a);

}

loops for-in

let Student={

name:"ved",

age:22,

cgpa:8.87,

section:2,

};

for(let a in Student){

    console.log(Student[a]);

}

String

let str="ved varshney";

console.log(str);

console.log(str[0]);

template string

let s=`hello madam ji`;

console.log(s);

let employee={

name : "ram",

age:30,

salary:20,

};

string interpolation

let str=`salary of ram is ${employee.salary} and age of ram is ${employee.age}`;

console.log(str);

string methods

let str="hellololo";

console.log(str.toLowerCase());

console.log(str.toUpperCase());

let s="    hey hello   ";

console.log(s.trim());

console.log(str.slice(1,4));

if there is no parameter in slice - print full string

console.log(str.slice());

console.log(str.concat("ved"));

console.log(str.replace("lo","h"));

console.log(str.replaceAll("lo","p"));

let s = prompt("enter name=");

console.log("@"+s+s.length);

let marks=[89,45,88,56,32,75,96];

console.log(marks);

let sum=0;

for(let i=0; i<marks.length; i++){

sum+=marks[i];

}

console.log(sum/marks.length);

let arr=[250,645,300,900,50];

for(let i=0; i<arr.length; i++){

    let off=arr[i]-arr[i]/10;

    arr[i]=off;

}

console.log(arr);

//if we want to access index element out of array size then - it show undefined

let arr=[1,2,3];

console.log(arr[3]); // undefined

// method of array

let arr=[12,34,56,78,45,65,73];

console.log(arr);

arr.push(99,100); // add at end (single or multiple we can add)

console.log(arr);

let val=arr.pop(); // delete from end

console.log(val);

console.log(arr);

console.log(arr.toString());

let brr=[5,12,45,33,67];

let crr=[11];

console.log(arr.concat(brr,crr)); // also add multiple array

arr.unshift(11); //add in start

console.log(arr);

 

let a = arr.shift(); // delete from start and return

console.log(a);

console.log(arr);

console.log(arr.slice(1,3)); // as it is substring

console.log(arr.slice());  // give full array

// splice method

arr.splice(2,1,560); // replace

console.log(arr);

arr.splice(2,2);  // delete

console.log(arr);

arr.splice(3,0,101,102);  // insert

console.log(arr);

arr.splice(2); //if we give only 1 parameter , splice delete all elements from given index

console.log(arr);